As Americans increasingly focus on healthy lifestyles, those concerned with maintaining their waistlines are once again faced with the task of shrinking that winter bulge. A study to be published in the June issue of The American Journal of Clinical Nutrition concludes that the dietary supplement, conjugated linoleic acid (CLA), reduces body fat mass in overweight, but otherwise healthy, adults by as much as nine percent.
The randomized, double blind, placebo-controlled study is the first to document the long-term safety and efficacy of CLA supplementation over a 12- month period without additional lifestyle or dietary restrictions.
This clinical trial is an ensuing study to previous animal and human trials that found CLA improves body composition by reducing fat and preserving lean muscle tissue. CLA has been clinically proven to aid in the maintenance of lean tissue and may help tone the body without necessarily causing overall weight loss.
It is thought to do this by decreasing the amount of fat stored after eating, increasing the rate of fat breakdown and metabolism -- helping the body use its existing fat for energy -- and decreasing the total number of fat cells.
"The results of this first long-term study indicate that CLA, taken for one year as a dietary supplement, safely improves the ratio of body fat to lean tissue in overweight, but otherwise healthy, adults," said Dr. Jean- Michel Gaullier, of Scandinavian Clinical Research in Kjeller, Norway, and project manager of the study. "Study participants who took 3.4 grams of CLA per day experienced a significant reduction in their body fat mass compared to those in the placebo group.
These results confirm a trend observed in previous short-term CLA studies." One hundred and eighty healthy men and women volunteers, ages 18 to 65, with a body mass index (BMI) of 25-30 kg/m2 (indicating that they were overweight) were randomized to receive gel capsules containing either 3.4 grams CLA-free fatty acid, 3.4 grams CLA-triglycerides or equivalent amounts of olive oil (placebo).
Patients were then followed for 12 months. Weight, BMI, vital signs and adverse events were recorded every three months. Body composition and blood samples were analyzed at regular intervals throughout the study, and participants were monitored continuously for any signs of serious adverse events.
At baseline, there was no difference between the groups for either weight, BMI, body fat mass or lean body mass. After only six months of observation, individuals taking either form of CLA experienced a significant reduction in body fat mass, while those in the placebo group saw no change. Daily caloric intake and exercise was not different between groups either at zero or 12 months and thus most likely did not play a role in body composition changes observed in the CLA groups.